Concept #1 Quiz

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Choose the best possible answer to the following questions about Key Concept 1 "'Metamorphism' and the agents that drive it."

This activity contains 9 questions.

Which of these is the most complete list of the agents of metamorphism, the agents that drive metamorphic transformations in rocks?

heat, pressure, parent rock heat, differential stress, chemically active fluids pressure, temperature, heat chemically active fluids, pressure, differential stress

Why is heat considered the most important agent of metamorphism?

Heat is similar to pressure since as depth increases, both temperature and pressure increase, causing metamorphism. Heat is the most fluid agent of metamorphism, where a rock can be affected by its ready application. Heat and pressure work together, but pressure is not important without high temperature.Heat provides the energy to drive chemical reactions that result in recrystallization.

How is “confining pressure” different from “differential stress”?

Confining pressure is when forces are applied equally in all directions, whereas differential stress is when forces are applied inequally. Confining pressure is when forces are applied inequally in different directions, whereas differential stress is when forces are applied equally. Confining pressure holds rocks in place, whereas differential stress is confining pressure applied in all directions. Confining pressure is present only in ocean water and increases with depth, whereas differential stress is present only within rocks.

What are the sources of heat necessary for contact or regional metamorphism? Choose all that apply.

energy released from impact of a meteorite or asteroidenergy released from radioactive decay inside the Earth energy released from thermal energy stored inside the Earth increasing temperatures associated with burial of sediment to a depth of about 2 kmfrom cooling magma nearby

Why do metamorphic changes occur at great depths? Choose all that apply.

Temperature increases with depth, causing rocks descending deeper to become progressively less stable and to metamorphose in response.Greater depths are the locations of greater temperature and pressure necessary for metamorphism. Temperature decreases with depth, causing rocks descending deeper to become progressively less stable and to metamorphose in response. Great depth is the area where most chemically active fluids are found, thus producing the most amount of hydrothermal metamorphism.

During metamorphism, what is the major effect of chemically active fluids?

the fluids aid in the movement of dissolved silicate constituents and facilitate growth of the mineral grains a prevention of partial melting so solid rocks can undergo very high temperature regional metamorphism an increase in the pressure in a deeply buried, regional-metamorphic zone the fluids facilitate the formation of schistosity and gneissic banding in hornfels and slate

What two ways can the parent rock affect the metamorphic process? Choose the two correct ways.

The metamorphic process can be stalled by certain overall chemical compositions of parent rocks, thus some rocks may not metamorphose in response to increasing heat.The mineral makeup of the parent rock determines the degree to which each metamorphic agent will cause change.The overall chemical composition of the metamorphic rock most times is the same as the composition of the parent rock, allowing an accurate interpretation as to what the parent rock was.Parent rocks completely change their mineral composition, making it very difficult to interpret what that parent rock was after metamorphism.

What concept is used to explain why an increase in heat and pressure produces metamorphism?

This causes a decrease in thermal energy so that chemical bonds between atoms are in equilibrium and recrystallize. This causes no change in the thermal energy and no change in the equilibrium.This causes an increase in thermal energy so that chemical bonds between atoms are out of equilibrium and recrystallize. None of these.

What about metamorphic rocks allows us to make a reasonable interpretation as to what the rock’s “parent rock” was?

The fact that the rock has undergone an increase in temperature and pressure.The “bulk” chemistry of the rock indicated by the minerals present in the rock and their proportions. The fact that the rock is recrystallized (textural change) indicated by the layered crystalline textures. It is an educated guess, but we can make only inferences based upon texture and metamorphic environment.

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